作物生长期间土壤可矿化氮的变化规律研究

在陕西杨凌中等肥力红油土上安排大田试验,定期分层采取土样,测定土壤可矿化氮和生物体氮,研究作物生长期间田间土壤可矿化氮的变化及其与生物体氮的关系.结果表明,土壤可矿化氮的分布具有明显的层次性,耕层高、下层少;土壤可矿化氮呈显著的阶段性变化,作物生长前期,含量低而稳定,后期显著增加,是前期的2倍;土壤可矿化氮不因施氮而减或增加,但在施有机肥的后期则显著增加;作物种类与种植与否对可矿化氮的影响较小;可矿化氮和生物体氮之间不仅无密切相关关系,前者仅为后者的12.0;.因此,难以用生物体氮的多少反映土壤供氮能力.

Study on the Variety of Mineralize-nitrogen During the Crop Growing in the Soil

By the field experiment in moderate fertilizer red-soil of Yangling, we took some soil samples periodical and laying, then determined the contents of Mineralize-nitrogen and Organism-nitrogen in the soil, the Variety of mineralize-nitrogen and the relation of mineralize-nitrogen and organism-nitrogen during the Crop growing were studied. The results showed the distribution of mineralize-nitrogen had obvious depth: the contents were higher at plough layer and lower at underlaying. The stage variety of mineralize-nitrogen was conspicuous .The contents were low and stability in prophase during the crop growing ,but outstanding raise in anaphase (even measure up to 2 times contents of prophase's). nitrogen manure had not positive influences to mineralize-nitrogen in the soil, but organic manure had marked increase in anaphase. The kind of crop had little influence. mineralize-nitrogen and organism-nitrogen in the soil had not only no closely dependence relation, but also the contents were indifferent(the contents of Mineralize-nitrogen were only 12.0% of organism-nitrogen's). Wherefore , it was difficult to reflect the provide ability of nitrogen by the contents of mineralize-nitrogen in the soil.